''Generation Um...'' is an existential day-in-the-life portrait that immerses the viewer in the downtown mindsets of John Wall (Keanu Reeves), a lost soul who's been circling the New York City drain for too long, and the two party girls he spends his birthday with- Violet (Bojana Novakovic) and Mia (Adelaide Clemens)- as they look for light in the darker aspects of their "family of circumstance" and the paths their self-destructive lives have taken.